Detachable electrical connectors



Dec. 9, 1941.

DETACHABLE ELECTRICAL CONNECTORS Filed July 26, 1940 I lnsulazz'oq Afnsulazzon 5 I ENTOR Az zh u Fish e1 2 BY 111$ ATZI'ORNEY A. w. FISHER2,265,363

Patented Dec. 9, 1941 UNITED STATES? area? OFFICE 2,265,363 DETACHABLEELECTRICAL CONNECTORS Arthur W. Fisher, Forest Hills, Pa;., assignor toThe Union Switch &"-Signal Company, Swissvale, Pa., a corporation ofPennsylvania.

Application July 26, 1940, Serial No. 347,807

3 Claims.

My invention relates in general to electrical connectors, and inparticular to detachable electrical connectors of the type whereby aplurality of external circuit conductors can be simultaneously connectedwith, or disconnected from,

the terminal posts of electrical devices such, for example, as theelectrical relays employed in railway signaling systems.

As is well known, the relays employed in railway signaling systems aregenerally provided with a relatively large number of contacts forcontrolling complicated circuit networks upon the proper operation ofwhich the safety of train movements depends. It occasionallybecomesnecessary to replace these relays for one reason or another, and it willbe apparent that if the external circuit wires are connected directly tothe relay terminal posts, as is now the general practice, the timerequired to disconnect these wires from the one relay and to connectthese wires to the other relay is likely to cause an undesirableinterruption in the operation of the system. Furthermore, there isalways the danger that in connecting the wires to the replacement relaya mix-up will occur which will cause a dangerous condition to exist.

One object of my present invention is to provide a detachable electricalconnector of the type described which will enable a reliable lowresistance connection to be made between the terminal posts of anelectrical relay and the external circuit wires that are to be connectedtherewith, and which will preclude any possibility of improper circuitconnections being made.

Another object of my invention is to provide a detachable electricalconnector which can be applied to relays which are already in servicewithout the necessity for making any changes in the construction of therelays, and which connector includes means to facilitate its attachmentto, and its detachment from the relay.

According to my invention the external circuit conductors, instead ofbeing secured directly to the relay terminal posts, are secured to otherterminal posts mounted on a detachable terminal plate adapted to besecured to the relay top plate. These other terminal posts are soarranged on the detachable terminal plate that when the detachableterminal plate is secured in place on the relay top plate, each terminalpost on the detachable terminal plate will align vertically with a.corresponding one of the terminal posts on the relay top plate, and eachterminal post on'the detachable terminal plate is secured to suitablespring members for frictionally engaging the corresponding relayterminal post to make good electrical contact therewith. The detachableterminal plate is further provided with one or more rotatable memberswhich are anchored against axial movement and which are adapted tocooperate with other members anchored in insulating brackets secured tocertain ones of the terminal posts on the relay top plate, whereby byrotating the rotatable members in the proper direction, the detachableterminal plate will be pulled toward or shoved away from the relay topplate to connect or disconnect the two sets of terminal posts.

I shall describe one form of electrical connector embodying myinvention, and shall then point out the novel features thereof inclaims.

In the accompanying drawing, Fig. l is a top plan View showing adetachable electrical connector embodying my invention applied to anelectrical relay. Figs. 2 and 3 are sectional views taken substantiallyon the lines 11-11 and III-III, respectively, of Fig. 1. Figs. 4 and 5are isometric views showing certain of the detail parts of the connectorillustrated in Figs. 1, 2 and 3.

Similar reference characters refer to similar parts in each of theseveral views.

Referring to the drawing, the electrical device to which I have shown myelectrical connector applied is an electrical relay of the type commonlyemployed in railway signaling systems, but it should be distinctlyunderstood at the outset that my electrical connector is not limited tothis particular application. The relay in the form illustrated comprisesthe usual top plate A provided with a pair of windings 2 which areadapted to be energized to cause operation of the relay and with aplurality of terminal posts 3 of the type which has been adopted asstandard by the Association of American Railroads for railway signalingpurposes. The terminal posts 3 are disposed in front of the windings 2,and in order, to facilitate convenient access thereto are arranged instepped rows.

,The electrical connector is designated as a whole by the referencecharacter B, and in the particular form illustrated comprises a terminalplate 4 of moulded insulating material such as Bakelite. a shape whichwill permit it to be secured to the top plate A in the position tosubstantially enclose the upper ends of the relay terminal posts, andformed in the under side of the terminal platearefa'plurality ofrectangular recesses 5 The terminal plate is generally of each of whichis adapted to receive the upper end of one of the relayterminal postswhen the connector is in place on the relay. The recesses 5 communicateat their upper ends with vertical holes 6, and secured within eachrecess by means of a terminal post 1 mounted in the associated hole 6 isa guide member 8 and two oppositely disposed vcontact fingers l9.

Each of the guide-2 member 8in"the form shown (see Fig. 5) comprises afiat strip of metal bent into a rectangular shape of such size that it ywill fit snugly within the recesses 5. The upper end wall of each guidememberisiormed bythe confronting ends of the strip, andmeachof theseends is provided with a semicircularmreces's .Bar. for receiving theshank of the associated termmalw post. The bottom wall of each sidemember is pierced by a hole 8b, the marginatwall of-whichis roundedupwardly for a purpose whiohwi-ll;

apart at theirclosest portions-a=distance that is e 7 less than thediameter-of the-relay-terminal posts, and it will be apparent;--thereiore,-=that' when the connector is placed on' the 'relay,-the twofingers in each'recess will -frictionally engage the oppositesides ofoneofthe relay-terminal-poststo 7 make electrical contacttherewitn Theparts are further so: proportioned that when the-fingers are engaging aterminal post; theiree ends-of the return bends will bear against theside walls -of the fingers to thereby-permit" the desired-contactpressure to be obtained --witha---li'ghtergaruge material. One advantageof the use of a lighter gauge materialis thattthere'is-less likelihoodthat it will takea permanent setfand-the life-"ofthe connector isaccordinglydengthened;

Each"terminal* post 1' is provided'atitsupper end with a washerlfl;'a"nut""ll- 'which secures the terminal post-to the 'terminal-plata twoWash ers 12' between which-thecnrved end of 'a-circuit conductor isadapted'to beficlampedand anim 7 sulating'nut- ['3 forclampinQthe-circuit conduc I torbetween the washers 1-2." The headfl-agof (each terminal post 7 :is made-squareand" is 'of suchsize that'it' prevents the-terminal postffronr turning .relatiVe to "the terminalplate.

' In vassembling 'each"contact: assembly: the 60 slotted portions of thetwo oppositelydis posedfin gers are placed under the head of:'thea'ssociated terminal post in superposed relationfbefore the head ofthe terminal post has enteredgthe asso-"f ciated recess 5, and the"guide member" 8*i then" placed on the'post by, springing itstside-walls apart, after which the guide member 'and:fingers are slidupwardly into the recess; .It will be seen; 7 therefore, that the.construction'of'the fingersand" guide members greatlyfacilitateassembly' of'the parts. a

It willbe noted gf'romlan insp tion of that some of; the contact'jas'sembIiesJare turned 90"from other "@1163 of lthe'setassemblie's;"This; construction fac'iiitates" aligning*therelaytermh" fingers out ofshape.

nal posts with the contact members of the connector when the connectoris to be attached to the relay.

It should be pointed out that without the guide members it wouldbe'possible in attempting to attach the connector to the relay to causethe ends of the relay terminal posts to engage the lower ends ofthecontact fingers, and if enough force were applied witlf the parts inthese positions, it would be possible to bend the contact However, withthe guide members constructed in the manner shown it isimpossible-to-cause the upper ends of the terminal posts to engage thefingers except in their properlycenteredvpositions, whereby damage tothe thus far described it will be apparent that due to the rlarge"number of contact members which are provided, and the fact thatrelatively high contact pressures are used, -an-appreciableamount of--force-is required to engage the connector with, and disengage it from-the-relay.= To facilitate engagement of the-connector with, and itsdisengagement from,-the-relay--I provide means embodying my-presentinvention; which means I shall nowdescribe.

As here shown, thesemeans comprise-two brackets I5-and 'l6,- preferablyof moulded insulating material; secured to the relay top plate atits-opposite sides by means 'of the terminal posts 3 of-the-middlerowofterminal posts in a man ner which-will'be apparent from aninspection of the-drawing. The outer end-of each bracket I 5 or H5extends outwardly beyond the associated terminal 'post, andds-provided"with a "threaded metalinsertlli The'inserts H cooperate with the--screw-th-rea'ded lower ends ofstuds IB'and l9,the upper ends "ofwhichextend upwardly with clearance through holes-- 2 0 formed -in-theterminal-plate and-have pinned'thereto ion' the uppersideofthe-terminalplate -hexago nalnuts 21; whereby" the stud may "berotated. Formed "on the studs iii-and EH3 directl'y above' their screwthreaded lower-ends areienla'rged'shank portions 23 which form-shoulders24-and'dispo'sed oneach stud between' the shoulders -24 an'dthe adjacentunder "side-of the-terminal plate is aithrust Washer 25' whichcooperates'with a'thru'st washer-26-mounted'on'theastud betweentheassociated nut 21- and the top 'of the terminal pl'a'teto' limitmovement of the studsi'in an' axial direction." It will beapparenttherefore, that while-the studs arefree'to rotate -relatived'pthe terminal plate, they are prevented from moving longitudinallyrelative" to: the' terininal'iplate; "It .will' also ;be apparent thatrotationp'of thestuds" in" one direction will cause them topull'the-oconnector towards the top gplater whereas *rotationiof thestuds in the opposite direction'willcause them to pushithe= connectoraway from the terminal plate. 7 The lengths of the enlarged shankportions 2 3"off the studsj'are such that' when "the shoulders romeo attheir lower ends are engaging jthe'tops of the' brackets. l5 and 'lii,the connector will occupy the proper vertical position for the contactassembly.

carried thereby'to. engage the endsof the-relay terminalzpostsinthedesired manner, and when this position of the connector is reached,'anyladditiona'l force 'exertedon" theistuds will' jam-the threadszof'the studs into ti'ghtfengagement with the threads of the insertsillfbutwill notlcaus'e' any force vto! be iexert'edion the parts offlth'e.

g connector 1 "If inesiredlme 'rnpperi lends .of{'.'tl 1'el studsmay'beprovidea'withsaw kerfs for the re ception of a screw driver, whereby theconnector may be attached or removed either by a screw driver or awrench.

In applying a connector of the type described to a relay for the firsttime, the excess nuts and Washers are first removed from the terminalposts of the relay, and if the relay has already been in service, allcircuit wires are also removed from the terminal posts. The brackets 15and 16 are then secured to the top plate by means of the terminal postsof the middle row after which each circuit wire is attached to theterminal post 1 of the detachable connector corresponding to theterminal post of the relay to which such wire was previously connectedor would be connected if the detachable terminal plate were notprovided. The connector is then placed in the proper vertical alignmentwith the terminal posts of the relay and is pulled downwardly into itsproper engaging position by rotating the studs 18 and iii in the properdirections.

When a relay has been provided with a connector of the type described,and it is subsequently desired to remove the relay from service, thestuds [8 and 19 are rotated in the proper direction to disengage thecontact fingers of the connector from the relay terminal posts. Theconnector is then lifted bodily ofi of the top plate of the relay andplaced on the top plate of the replacement relay, after which theconnector is again pulled downwardly to the position shown in thedrawing by means of the studs l8 and I9.

One advantage of an electrical connector embodying my invention is thatit can be applied to relays which are already in service without disturbing any parts of the relay.

Although I have herein shown and described only one form of electricalconnector embodying my invention, it is understood that various changesand modifications may be made therein within the scope of the appendedclaims without departing from th spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. The combination with an electrical device having a plurality ofprojecting terminal posts for establishing external circuit connectionswith the device and a detachable electrical connector comprising aterminal plate carrying members for engaging said terminal posts toestablish electrical connection therewith, of an insulating membersecured to said device by means of certain ones of said terminal posts,and means secured to said terminal plate and cooperating with saidmember to facilitate the engagement of the contact members or" saidconnector with, or their disengagement from, said terminal posts.

2. The combination with an electrical device having a plurality ofprojecting terminal posts for establishing external circuit connectionswith the device and a detachable electrical connector comprising aterminal plate carrying contact members for frictionally engaging saidterminal posts to establish electrical connection therewith, of twoinsulating members secured to said device at its opposite sides by meansof certain ones of said terminal posts and each provided with a threadedmember, and two studs rotatably mounted in said terminal plate and onecooperating with each of said threaded members for moving said connectortoward or away from said device to eiiect the engagement of said contactmembers with or their disengagement from said terminal posts.

3. The combination with an electricaldevice having a plurality ofprojecting terminal posts for establishing external circuit connectionswith the devic and a detachable electrical connector comprising aterminal plate carrying contact members for frictionally engaging saidterminal posts to establish electrical connection therewith, of twomoulded insulating members secured to said device at its opposite sidesby means of certain ones of said terminal posts and each provided with athreaded opening, two studs rotatably mounted intermediate their ends inopenings formed in said terminal plate and each provided on the outerside of said terminal plate with means for engaging the stud to rotateit and on the under side of the plate with a threaded end forcooperation with a different one of the threaded openings in saidinsulating member and with an enlarged shank portion forming a shoulderWhich cooperates with the associated insulating member to position saidconnector relative to said device when said studs are screwed into saidthreaded openings, the parts being so proportioned that when saidshoulders are engaging said insulating members said contact members willoccupy the proper positions relative to said terminal posts to establishelectrical contact therewith.

ARTHUR W. FISHER.

